// Based on public domain code written in 2012 by Samuel Neves

#include "blake2s.h"
#include "r2sapi.h"

static const uint32_t blake2s_IV[8] =
{
	0x6A09E667UL, 0xBB67AE85UL, 0x3C6EF372UL, 0xA54FF53AUL,
	0x510E527FUL, 0x9B05688CUL, 0x1F83D9ABUL, 0x5BE0CD19UL
};

const byte blake2s_sigma[10][16] =
{
	{  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15 } ,
	{ 14, 10,  4,  8,  9, 15, 13,  6,  1, 12,  0,  2, 11,  7,  5,  3 } ,
	{ 11,  8, 12,  0,  5,  2, 15, 13, 10, 14,  3,  6,  7,  1,  9,  4 } ,
	{  7,  9,  3,  1, 13, 12, 11, 14,  2,  6,  5, 10,  4,  0, 15,  8 } ,
	{  9,  0,  5,  7,  2,  4, 10, 15, 14,  1, 11, 12,  6,  8,  3, 13 } ,
	{  2, 12,  6, 10,  0, 11,  8,  3,  4, 13,  7,  5, 15, 14,  1,  9 } ,
	{ 12,  5,  1, 15, 14, 13,  4, 10,  0,  7,  6,  3,  9,  2,  8, 11 } ,
	{ 13, 11,  7, 14, 12,  1,  3,  9,  5,  0, 15,  4,  8,  6,  2, 10 } ,
	{  6, 15, 14,  9, 11,  3,  0,  8, 12,  2, 13,  7,  1,  4, 10,  5 } ,
	{ 10,  2,  8,  4,  7,  6,  1,  5, 15, 11,  9, 14,  3, 12, 13 , 0 } ,
};

static inline void blake2s_set_lastnode( blake2s_state *S )
{
	S->f[1] = ~0U;
}


/* Some helper functions, not necessarily useful */
static inline void blake2s_set_lastblock( blake2s_state *S )
{
	if( S->last_node ) blake2s_set_lastnode( S );

	S->f[0] = ~0U;
}


static inline void blake2s_increment_counter( blake2s_state *S, const uint32_t inc )
{
	S->t[0] += inc;
	S->t[1] += ( S->t[0] < inc );
}


static inline void blake2s_init_set_pointers(blake2s_state *S)
{
	// Set aligned pointers. Must be done in constructor, not in Init(),
	// so assignments like 'blake2sp_state res=blake2ctx' work correctly
	// even if blake2sp_init is not called for 'res'.
	S->buf = (byte *) ALIGN_VALUE(S->ubuf, BLAKE_ALIGNMENT);
	S->h   = (uint32_t *) (S->buf + 2 * BLAKE2S_BLOCKBYTES);
	S->t   = S->h + 8;
	S->f   = S->t + 2;
}

/* init2 xors IV with input parameter block */
void blake2s_init_param( blake2s_state *S, uint32_t node_offset, uint32_t node_depth)
{
	int i;

	blake2s_init_set_pointers(S);
	
	// Clean data.
	memset( S->ubuf, 0, sizeof( S->ubuf ) );
	S->buflen = 0;
	S->last_node = 0;

	for( i = 0; i < 8; ++i )
		S->h[i] = blake2s_IV[i];

	S->h[0] ^= 0x02080020; // We use BLAKE2sp parameters block.
	S->h[2] ^= node_offset;
	S->h[3] ^= (node_depth<<16)|0x20000000;
}


static _forceinline uint32_t rotr32( const uint32_t w, const unsigned c )
{
	return ( w >> c ) | ( w << ( 32 - c ) );
}


#define G(r,i,m,a,b,c,d) \
	a = a + b + m[blake2s_sigma[r][2*i+0]]; \
	d = rotr32(d ^ a, 16); \
	c = c + d; \
	b = rotr32(b ^ c, 12); \
	a = a + b + m[blake2s_sigma[r][2*i+1]]; \
	d = rotr32(d ^ a, 8); \
	c = c + d; \
	b = rotr32(b ^ c, 7);


static void blake2s_compress( blake2s_state *S, const byte block[BLAKE2S_BLOCKBYTES] )
{
	uint32_t m[16];
	uint32_t v[16];
	size_t i;
	uint32_t r;

	for( i = 0; i < 16; ++i )
		m[i] = RawGet4( block + i * 4 );

	for( i = 0; i < 8; ++i )
		v[i] = S->h[i];

	v[ 8] = blake2s_IV[0];
	v[ 9] = blake2s_IV[1];
	v[10] = blake2s_IV[2];
	v[11] = blake2s_IV[3];
	v[12] = S->t[0] ^ blake2s_IV[4];
	v[13] = S->t[1] ^ blake2s_IV[5];
	v[14] = S->f[0] ^ blake2s_IV[6];
	v[15] = S->f[1] ^ blake2s_IV[7];

	for ( r = 0; r <= 9; ++r ) // No gain on i7 if unrolled, but exe size grows.
	{
		G(r,0,m,v[ 0],v[ 4],v[ 8],v[12]);
		G(r,1,m,v[ 1],v[ 5],v[ 9],v[13]);
		G(r,2,m,v[ 2],v[ 6],v[10],v[14]);
		G(r,3,m,v[ 3],v[ 7],v[11],v[15]);
		G(r,4,m,v[ 0],v[ 5],v[10],v[15]);
		G(r,5,m,v[ 1],v[ 6],v[11],v[12]);
		G(r,6,m,v[ 2],v[ 7],v[ 8],v[13]);
		G(r,7,m,v[ 3],v[ 4],v[ 9],v[14]);
	}

	for( i = 0; i < 8; ++i )
		S->h[i] = S->h[i] ^ v[i] ^ v[i + 8];
}


void blake2s_update( blake2s_state *S, const byte *in, size_t inlen )
{
	while( inlen > 0 )
	{
		size_t left = S->buflen;
		size_t fill = 2 * BLAKE2S_BLOCKBYTES - left;

		if( inlen > fill )
		{
			memcpy( S->buf + left, in, fill ); // Fill buffer
			S->buflen += fill;
			blake2s_increment_counter( S, BLAKE2S_BLOCKBYTES );

#ifdef USE_SSE
#ifdef _WIN_32 // We use SSSE3 _mm_shuffle_epi8 only in x64 mode.
			if (SIMD_Version.SSE2)
#else
			if (SIMD_Version.SSE3S)
#endif
				blake2s_compress_sse( S, S->buf );
			else
				blake2s_compress( S, S->buf ); // Compress
#else
			blake2s_compress( S, S->buf ); // Compress
#endif

			memcpy( S->buf, S->buf + BLAKE2S_BLOCKBYTES, BLAKE2S_BLOCKBYTES ); // Shift buffer left
			S->buflen -= BLAKE2S_BLOCKBYTES;
			in += fill;
			inlen -= fill;
		}
		else // inlen <= fill
		{
			memcpy( S->buf + left, in, (size_t)inlen );
			S->buflen += (size_t)inlen; // Be lazy, do not compress
			in += inlen;
			inlen -= inlen;
		}
	}
}


void blake2s_final( blake2s_state *S, byte *digest )
{
	int i;
	if( S->buflen > BLAKE2S_BLOCKBYTES )
	{
		blake2s_increment_counter( S, BLAKE2S_BLOCKBYTES );
		blake2s_compress( S, S->buf );
		S->buflen -= BLAKE2S_BLOCKBYTES;
		memcpy( S->buf, S->buf + BLAKE2S_BLOCKBYTES, S->buflen );
	}

	blake2s_increment_counter( S, ( uint32_t )S->buflen );
	blake2s_set_lastblock( S );
	memset( S->buf + S->buflen, 0, 2 * BLAKE2S_BLOCKBYTES - S->buflen ); /* Padding */
	blake2s_compress( S, S->buf );

	for( i = 0; i < 8; ++i ) /* Output full hash  */
		RawPut4( S->h[i], digest + 4 * i );
}

